A modular computer simulation, program for absorption systems has been developed, which makes it possible to simulate various cycle configurations. The user supplies information about operating conditions, as well as characteristics of the various subunits and working fluids of the system. In addition he conveys to the computer an image of the cycle. Based on this information, the program calculates the temperature, composition, flowrate and pressure at each state point of the system and the heat quantities at each unit.

The code is based on subroutines modelling each of the absorption system's units and a main program which links them up according to the user's specification. The program has been tested on single and double stage absorption heat pumps and heat transformers, with lithium bromide - water and water-ammonia as the working fluids. The results have been compared with experimental data from tests of LiBr-H₂0 heat transformer, giving good agreement.

Units: I-P